OBJECTIVE To our knowledge, only 2 cases of pancreatic neuroendocrine tumors have been described as the source of corticotropin-releasing hormone (CRH) in Cushing's syndrome. Here, we describe a case of ectopic adrenocorticotrophic hormone (ACTH-) and CRH-production caused by a pancreatic neuroendocrine tumor. METHODS We analyzed and summarized the patient's medical history, physical examination results, laboratory data, imaging studies, and histopathologic results. RESULTS An endocrinologic workup revealed massive ACTH-dependent hypercortisolism. Pituitary magnetic resonance imaging (MRI) showed no pathologic findings and led to extensive imaging in search of the suspected ectopic lesion. Ketoconazole treatment was initiated. Rapid deterioration of the patient's clinical condition due to escalating cortisol levels and resulting sepsis required an emergency adrenalectomy to control the hypercortisolism. A positron emission tomography-computed tomography (PET-CT) scan revealed a hepatic lesion, which was biopsied. Histology of the lesion showed a well-differentiated endocrine tumor. Subsequent scintigraphy with octreotide (a somatostatin [SMS] analog) detected a pancreatic tumor, which was endosonographically confirmed. The initiated SMS therapy was followed by a distal splenopancreatectomy and a right hemihepatectomy. Immunostaining of the specimen showed positive expression for CRH and ACTH. CONCLUSIONS We conclude that SMS-scintigraphy did have an additional diagnostic benefit compared to PET-CT. In hypercortisolemic patients, rapid endocrinologic evaluation is crucial to prevent rapid deterioration and a possible fatal outcome.